Mechanical modelling of oblique convergence in the Zagros, Iran     

Philippe Vernant  Jean Chéry 《Geophysical Journal International》2006,165(3):991-1002

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Two-dimensional and three-dimensional finite element modelling of mantle processes beneath central South Island, New Zealand     

Zhen Liu  Peter Bird 《Geophysical Journal International》2006,165(3):1003-1028

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Crustal and upper mantle structure of the Western Carpathians from CELEBRATION 2000 profiles CEL01 and CEL04: seismic models and geological implications   总被引：2，自引：0，他引：2  

P. &#;roda  W. Czuba  M. Grad  A. Guterch  A. K. Tokarski  T. Janik  M. Rauch  G. R. Keller  E. Hegedüs  J. Vozár  CELEBRATION Working Group 《Geophysical Journal International》2006,167(2):737-760

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广西大容山S-型花岗岩套   总被引：6，自引：1，他引：6  

方清浩  冯君储  何令仪 《岩石学报》1987,3(3)

大容山S-型花岗岩套位于华南海西地槽褶皱带的钦州地槽区。岩套包括侵入岩和火山岩两个建造和三个岩相:侵入岩相——堇青石黑云母花岗岩;次火山岩相——自碎斑状紫苏辉石花岗斑岩;火山岩相——辉石英安岩和英安流纹岩。它们是在麻粒岩相条件下,由过铝成质源岩重熔产生的S-型花岗岩浆派生而来。主体形成于海西晚期。从东向西岩套具有规律的演化趋势。  相似文献   

山东玲珑和郭家岭岩体的同位素年龄及其地质意义   总被引：18，自引：2，他引：18  

胡世玲  王松山  桑海清  裘冀  张任祜 《岩石学报》1987,3(3)

本文采用~(40)K-Ar/~(39)Ar快中子活化和K-Ar稀释法定年技术对玲珑岩体和郭家岭岩体进行了年龄测定。~(40)Ar/~(39)Ar阶段加热年龄谱表明,玲珑岩体和郭家岭岩体的坪年龄分别为164.2±0.7Ma和134.8±1.7Ma,其形成时代同属燕山期,为同一成因不同阶段的产物。同位素年龄提供的数据支持了两岩体为交代混合岩化的成因观点。~(40)Ar/~(39)At和K-Ar年龄结果还表明:角闪石和黑云母均是~(40)Ar/~(39)Ar理想定年矿物,对K-Ar法而言,角闪石最理想,黑云母次  相似文献   

天山古生代增生造山作用及其构造转换事件     

王博  宋芳  倪兴华  曹婷婷  刘珈硕  钟凌林  孙朝晨  孙雨欣  邓聚  李盈莹  朱鑫  刘洪升  何智远 《地质学报》2022,96(10):3514-3540

天山造山带自新元古代以来，经历了漫长而复杂的俯冲增生造山作用和陆内构造活化过程，属于典型的复合型造山带。基于近年研究进展，本文对伊犁、境内外中天山和南天山构造带前寒武纪基底、古生代沉积序列、多期陆缘弧岩浆岩和构造缝合带的变形变质特征、形成环境和年代学等进行了总结分析，梳理了天山古生代增生造山作用中的三次重要构造转换事件及其地质记录。① 伊犁南北两缘、中天山、南天山和塔里木北缘，均发育中奥陶世—志留纪的大陆弧岩浆作用，伊犁北缘、南天山 塔里木北部早古生代沉积环境发生显著变化，表明天山 塔里木北缘在中—晚奥陶世发生了从被动陆缘向活动陆缘的转换。② 伊犁南、北两缘和中天山的早古生代岩层在晚志留世—早泥盆世普遍发生了强烈的韧性变形和角闪岩相变质作用，其上不整合覆盖有弱变形未变质的晚泥盆世—石炭纪火山 沉积地层；该区域不整合是哈萨克斯坦微大陆拼合事件在研究区的构造响应，也标志着准噶尔洋和南天山洋的俯冲方式在泥盆纪发生了由前进式（东太平洋型）向后撤式（西太平洋型）的构造转换，导致伊犁和中天山在晚泥盆世—石炭纪经历了伸展背景下的大陆弧岩浆作用，在南天山 塔里木北缘则形成了一系列弧后有限洋盆。③ 天山各构造单元及其边界缝合带中普遍发育晚石炭世逆冲推覆构造和二叠纪走滑韧性剪切带、晚石炭世—早二叠世滑塌堆积和二叠纪后造山岩浆岩，指示晚石炭世—早二叠世发生了由汇聚造山向陆内构造的转换。这些构造转换事件是认识古亚洲洋各分支洋盆从初始俯冲、俯冲方式转换到俯冲终结过程的基础，也是探讨增生造山动力学的关键。  相似文献   

An assessment of Yarsagumba (Ophiocordyceps sinensis) collection in Dhorpatan Hunting Reserve,Nepal     

BarnaBahadur THAPA  Saroj PANTHI  Rajesh KumarRAI  UttamBabu SHRESTHA  Achyut ARYAL  Sabina SHRESTHA  Bhushan SHRESTHA 《山地科学学报》2014,11(2):555-562

Yarsagumba （Ophiocordyceps sinensis）, an endemic species to the Himalayas and Tibetan Plateau, is one of the most valuable medicinal mushrooms in the world. In Nepal, it is distributed largely in isolated patches of alpine grasslands of 3,000-5,000 m elevation. Although it is reported from 27 northernmost districts of Nepal, the local distribution pattern of this species is largely unknown. Furthermore, the collection system and local management regime of this species are not well documented. We conducted a field survey at Dhorpatan Hunting Reserve （DHR） among the different stakeholders in January-June 2012 to assess collection sites, patterns and trends and to understand the management regime. We estimated that about 75 kg of Yarsagumba is collected every year from DHR and the amount has been declining since 2008. To manage the resource, locals have initiated regulating the collection by issuing permits, taxing to the collectors, and monitoring the activities of harvesters with the help of park authorities. The revenue generated at local level from the permits has been used for community developmental activities.  相似文献   

Evolutionary process and development implications of traditional trade routes in the Himalayan region     

Wu  Shihai  Yan  Jianzhong  Zhang  Yili  Peng  Ting  Su  Kangchuan 《地理学报(英文版)》2022,32(9):1847-1865

Journal of Geographical Sciences - Traditional trade routes that penetrate the natural barrier of the Himalayas are critical for connecting major Chinese and South Asian markets. Research on these...  相似文献   

Geochronology and geochemistry of Middle Devonian mafic dykes in the East Kunlun orogenic belt,Northern Tibet Plateau: Implications for the transition from Prototethys to Paleotethys orogeny   总被引：3，自引：0，他引：3  

Fuhao Xiong  Changqian Ma  Hong’an Jiang  Bin Liu  Jian Huang 《Chemie der Erde / Geochemistry》2014

The tectonic transition from Prototethys to Paleotethys orogeny in the East Kunlun orogenic belt is not completely clear, and is a major unresolved geologic issue in Northern Tibet Plateau. Here, we present zircon geochronology, whole-rock elemental and zircon Hf isotopic geochemistry for newly discovered mafic dykes in the East Kunlun orogenic belt, to provide constraints on this issue. The studied mafic dykes are hornblende gabbros, consisting of hornblende (60–65 vol.%), plagioclase (15–25 vol.%) and augite and biotite (0–5 vol.%). LA–ICP–MS zircon U–Pb dating shows that these mafic dykes were emplaced at about 393 Ma. All the mafic dykes are characterized by high contents of CaO (8.82–11.48 wt.%), MgO (9.07–11.39 wt.%), V (275–336 ppm), Cr (370–467 ppm) and Ni (78.3–120 ppm), with high Mg# (63–67), flat CI-normalized REE distribution and depleted ?Hf(t) values (2.03–5.35), showing tholeiitic affinities and geochemical characteristics similar to those of mid-ocean ridge basalts. They were derived from low degree (about 5–15%) partial melting of a fertile spinel lherzolite source, which have been metasomatized by fluids introduced to the mantle by former subducted slab. The geologic–petrologic evidence suggests that the mafic dykes were emplaced in a shift tectonic setting related to continental rifting, which was caused by the extensional collapse related to the lithospheric thinning after the Prototethys orogeny. The delamination-induced thermal disturbance and extensional decompression triggered partial melting of the mantle and the emplacement of the mafic dykes. Combined with previous work, we propose that the Middle Devonian mafic dykes may be the early magmatic response to the transition from Prototethys to Paleotethys marking the opening of the Paleotethys in the East Kunlun orogenic belt.  相似文献   

Tectonic evolution of an active tectonostratigraphic boundary in accretionary wedge: An example from the Tulungwan-Chaochou Fault system,southern Taiwan     

《Journal of Structural Geology》2014

The Tulungwan-Chaochou Fault system in southern Taiwan represents the boundary between a slate belt of moderate metamorphic grade and a relatively unmetamorphosed fold-and-thrust belt. The offset between hanging wall and footwall of this fault ranges from 7 to 11 km and is considered one of the major tectonostratigraphic faults in Taiwan. This 75-km-long fault system is also one of the most conspicuous topographic features in Taiwan. The geometry, kinematic history and associated subsidiary structures have not been resolved. Field mapping of fabrics and brittle faults show that a 45-km-long west-northwest-vergent antiform defined by folded slaty cleavage exists in the hanging wall of the fault. This antiform has not been previously described and apparently formed in a brittle environment. The flat crest and tight forelimb of the antiform suggests a two-stage deformation model composed of a fault-bend fold followed by a trishear fold. We infer that regional scale fold is associated with a thrust that splays upward from the main detachment.  相似文献